I did an installation today on a Dell R250 with a PERC H355 controller. What I understand is that the H355 is not supported so I have set up the disks in 'Non-RAID mode' and installed Proxmox 7.1 with ZFS RAID 1 on 2 disks. So far it looks like it runs just fine. I have tested to boot with first just one disk inserted and then the other way around and it works as expected.
I hope yes. I've checked and checked. Officialy on Dell SIte the R350 is supported by Canonical Ubuntu Server LTS 20.04 and 22.04 i immagine.
also the support answered me:
We don't keep a hardware compatibility list. But PVE 7.2 uses a 5.15 kernel that's based on the one in Ubuntu 22.04.
If those servers are compatible with Ubuntu 22.04, they should be compatible with PVE 7.2 as well.